Research On Compound Behavior Of Pure Aluminum And Copper By Tube High-pressure Shearing

Compound of pure aluminum (99.98% and 99.999%) and pure copper (99.98%) are processed by tube high-pressure shearing (t-HPS) at several strain level. The microstructure of compound interface is characterized by optical microscope (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and energy dispersive spectrum (EDS) analysis. The bonding strength is defined by the shear strength at the bonding surface measured in shear test. The bonding strength, which is influenced by the deformation condition, increases with increasing average strain level and saturates at high strain which suggest a metallurgical bonding obtained at the interface. The hydrostatic pressure and strain rate play a minor role in bonding strength at high hydrostatic pressure and low strain rate level. However, sample surface preparation is significant in obtaining metallurgical bonding. The inner metal undergo more serious work hardening as a strain gradient along radius direction of the tube. Thus, the inner metal of composite should have a lower work-hardening exponent for tube high-pressure shearing processing. During the tube high-pressure shearing, high purity (99.999%) and low purity (99.98%) aluminium undergo different microstructure and texture evolution. Moreover, significant diffusion phenomenon was found across the interface of copper and aluminium. The surface expanding is mainly induced by the sample thinning during mandrel pressing and the kinks initiated during shearing process and the latter factor dominant.